3.6 pentastar 2020 major problems - Is the newer engine better in 2025 etc.

[ShadowsPapa]

My '19 Wrangler right bank and one cam completely rounded and the rocker was flat by the time I was able to get them to acknowledge the issue. I'm surprised it wasn't misfiring. it sounded like a diesel, the tick was that bad.

So, I'm now picking up a JTDR this week. At least it's supposed to sound like a diesel!

The Pentastar has been around for a good couple of decades now; I don't see them having a fix for the issue until they bring in a clean sheet new motor build.

The prior issues with the first 3.6 wasn't the same issue. This specific issue is since 2016.

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[Toothgnasher]

The prior issues with the first 3.6 wasn't the same issue. This specific issue is since 2016.

Well, its now a decade, so I'm still going to say it's unlikely to be fixed w/out a clean sheet.

 

[ShadowsPapa]

Well, its now a decade, so I'm still going to say it's unlikely to be fixed w/out a clean sheet.

So far it appears only forum members have knowledge of the root cause and the fix. So you are likely correct.

 

[Deleted member 67086]

Easy -
The first generation Pentastar 3.6 did not have VVL.
The 1st gen had roller followers on a single cam lobe.
Their issue was the needle bearings in the rollers on the intake followers.

These engines are a PUG - Pentastar UpGrade engine. They have VVL
They also have rollers for the LOW LIFT portion of the intake followers while the high lift portion of the followers rubs on a cam lobe with NO rollers at all.
The rollers on the PUG don't fail.
The high lift portion of the follower and associated cam lobe fail.

First gen - full intake follower rollers using needle bearings, needle bearings failed.
PUG - rollers are fine. They do not fail. The high lift part fails - the part that rubs.

FCA has also replaced the first gen follower with a different roller design to address the issues in the first gen with the ROLLER NEEDLE BEARNGS failing.

Needle bearings are a touchy topic among performance people who run roller cams in their legacy/classic cars. Some companies did away with the needle bearings because they failed.

We know it's not the same cause because -
1st gen rollers had needle bearings that fail
2nd gen (PUG) do not see needle bearing failures in intake or exhaust.
The VVL high lift portion is what fails on the PUG - NOT the rollers

Same symptoms, same "fix" as far as replacing parts, but very different causes.

Lumping the first gen failures in with the PUG failures shows a lack of knowledge as far as what actually failed, and how very different they are.

You may have a cough and achy joints - and your neighbor may have the same while you have a common cold and your neighbor has pneumonia.
You both cough and ache, very different causes.

So what is the root cause of the current GEN 3 failure?? I seem to recall that the previous gen needle bearing failures were predominantly on the passenger side intake bank, similar to the gen 3. If the previous gen was solely the needle bearings, wouldn’t it have occurred more evenly on either bank? It just seems like there is some issue that occurs on the passenger side bank that spans generations, and rocker arm type

The current generation 3.6L fails the high lift lobe on the cam. When it is in high lift mode, anything beyond 2700 rpm, the high lift cam is not roller it is friction based like and old school flat tappet.

Plenty of speculation around metallurgy, surface finish, and oiling needs. Many revisions of software have been implemented to control, oil pressure,cam position, and time spent at a given RPM, as well as active cleaning cycling of the cam phazers and the control solenoids.

My two cents: limit your time at high RPM, change your oil often, and if you run high rpm use a heavier oil.

So it sounds like the root cause is still unknown, at least by us anyway. My two cents worth is that Stellantis knows the root cause and has determined the failure rate is acceptable compared to the cost of fixing the issue.

 

[ShadowsPapa]

So what is the root cause of the current GEN 3 failure??

GEN 3?????
What's Gen 3?

So far only internet/forum members have figured out the "root cause".
The "root cause" isn't known for the PUG engine HIGH LIFT follower failures.
(not for a fact)

The prior, first generation, was the needle bearings. New design followers have resolved that according to techs out there.

We only know which parts fail on the PUG, no "common knowledge" actual cause of the failure.

 

[DAVECS2]

Well being that no recent developed valvetrain has been made with friction lifter follower tech, my guess is the oil and metallurgy is not designed for it. Neither one is up to the task of meeting todays requirements for milage emissions and heat. So of you spend enough time outside of the curve it fails.

 

[ShadowsPapa]

Well being that no recent developed valvetrain has been made with friction lifter follower tech, my guess is the oil and metallurgy is not designed for it. Neither one is up to the task of meeting todays requirements for milage emissions and heat. So of you spend enough time outside of the curve it fails.

Mine have always spent a lot of time over 3,000 RPM. (one reason I do oil analysis to set a baseline and watch for trends).
On the other hand - it doesn't really appear to fit any use pattern. Of course no one is going to say honestly exactly how they use their engine, how hard they run it and so on.

 

[Deleted member 67086]

GEN 3?????
What's Gen 3?

So far only internet/forum members have figured out the "root cause".
The "root cause" isn't known for the PUG engine HIGH LIFT follower failures.
(not for a fact)

The prior, first generation, was the needle bearings. New design followers have resolved that according to techs out there.

We only know which parts fail on the PUG, no "common knowledge" actual cause of the failure.

Thank you, so we do not know the root cause for the PUG. We just know the majority of the issues are occurring on the intake followers/cam on the passenger side.

 

[ShadowsPapa]

Thank you, so we do not know the root cause for the PUG. We just know the majority of the issues are occurring on the intake followers/cam on the passenger side.

It took 30 seconds to find a few JK owners with the follower roller failures on the left bank or bank #2
Can't say which side happened the most, but it's apparently not uncommon for the left to fail on the first version of the Pentastar 3.6 without VVL

If we as ordinary people on the internet knew of the actual "root cause" of all of these failures on the PUG valvetrain, we'd be getting jobs at FCA. So far from what I've seen, even Chrysler techs are only able to give it their best guess based on hands-on experiences. So how will anyone else here know?

 

[Cwg33]

Come on, these are business people. Whether you believe in Stellantis acumen is a different discussion, but if they knew the answer and could fix it easily out-weighing the cost of dealer fixes it would have been done. It’s obviously not such a huge cost % outlier vs warranty expense that they have to resolve to remain solvent.

Does it suck for affilicted drivers, YES!

Is the company keeping some secret fix for 2025 cams, I highly doubt it. They don’t want return fixes. It’s not efficient for cost projections and the almighty stock price.

 

[DAVECS2]

Mine have always spent a lot of time over 3,000 RPM. (one reason I do oil analysis to set a baseline and watch for trends).
On the other hand - it doesn't really appear to fit any use pattern. Of course no one is going to say honestly exactly how they use their engine, how hard they run it and so on.

Whats alot of time? Minutes/hours all at once. Accumulating heat is what will kill it. My guess is you regularly change your oil and do it more than the recommended oil change. So you reset your additive package every 5k miles.

People are putting huge wheel packages on these and then spend hours cruising at 2500 or greater rpm putting heat into the highlift valvetrain at high load. If you run stock or stockish, the occasion off road adventure, or spiritede accelerations will possibly never amount to enough input to break down oil shear and push the metal surface beyond its wear point, especially if not loaded and hot.

 

[Deleted member 67086]

It took 30 seconds to find a few JK owners with the follower roller failures on the left bank or bank #2
Can't say which side happened the most, but it's apparently not uncommon for the left to fail on the first version of the Pentastar 3.6 without VVL

If we as ordinary people on the internet knew of the actual "root cause" of all of these failures on the PUG valvetrain, we'd be getting jobs at FCA. So far from what I've seen, even Chrysler techs are only able to give it their best guess based on hands-on experiences. So how will anyone else here know?

Well, when you were rather critical of the Pentastar lawsuit, saying different issue different root cause, it gave the impression you knew the root cause.

Anyway, I agree 100%, all we know is what we find on the Internet. With the PUG, again based on what I’ve read, the issue seems to happen more frequently on bank 1. Not saying it can’t happen on bank 2, just seemed most of what I was reading indicated there was some sort of tie in with bank 1. That seemed similar to what I had read as well with the needle bearing follower issue in that it seemed to be more frequent on bank 1.

In reality do we really know the root cause of either issue? We know replacing the needle bearing followers seemed to fix the issue, but then again, that issue typically surfaced in higher miles, like 80k plus. Do we really know if anyone had a second occurrence or not? Do we really know if the needle bearings were the root cause, or could it be some other oiling issue that caused the needle bearings to fail? You are right, if we knew for sure, we’d have different jobs.

 

[Hootbro]

GEN 3?????
What's Gen 3?

I think it stems from when the 1st Gen engines got the redesigned oil filter and housing in 2014. People on the internet then attached "GEN 1" and "Gen 2" to differentiate from 2013 back and 2014 forward. When the PUG came into being, then "Gen 3" got into the lexicon.

Officially, I do not think FCA considers the 2014 a generational change and there really is only two generations of the Pentastar. The Maserati Twin Turbo 3.0 is it's own thing with the lower short block to this day still built on the Gen 1 architecture.

 

[ShadowsPapa]

I think it stems from when the 1st Gen engines got the redesigned oil filter and housing in 2014. People on the internet then attached "GEN 1" and "Gen 2" to differentiate from 2013 back and 2014 forward. When the PUG came into being, then "Gen 3" got into the lexicon.

Officially, I do not think FCA considers the 2014 a generational change and there really is only two generations of the Pentastar. The Maserati Twin Turbo 3.0 is it's own thing with the lower short block to this day still built on the Gen 1 architecture.

LOL - ok, oil filter and housing made a generation to some. Interesting.
I wonder what they call those with the intake on the other side if an oil filter change is major?
I guess it's "whatever".

Too bad some of the planned changes in 2015 never took, and we lost the flex-fuel possibility.

 

[Hootbro]

LOL - ok, oil filter and housing made a generation to some. Interesting.
I wonder what they call those with the intake on the other side if an oil filter change is major?
I guess it's "whatever".

Too bad some of the planned changes in 2015 never took, and we lost the flex-fuel possibility.

It is one of things that you had to been in the moment back then. Prior to 2013, oil coolers and housing were leaking a hell of a lot more than today and past 2014. Also in 2014, the heads were revised to addressed dropped valve seat issue and a few other things. The 2014+ while not 100 perfect, they were an improvement. The PUG in relation to the Wrangler would not be a thing for 4 more years.

I know it that OCD brain of yours you are screaming to correct it every time it is mentioned of "Gen 3", I would let it go.

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